High voltage (HV, herein defined as voltages of 72.5 kV or more) circuit breakers often interrupt electrical current by the separation of two arcing contact members—a first arcing contact member and a second arcing contact member—from one another. After the separation of the two arcing contact members, the electrical current continues to flow between them and is carried by an arc between the two contacts. For interrupting the current, the arc must be extinguished and re-ignition must be suppressed. In gas-insulated type circuit breakers, the arc is extinguished using a dielectric gas such as SF6. The dielectric gas also reduces the risk of re-ignition and dielectric breakdown.
However, especially at higher voltages (e.g. 380 kV or more), there is a need for further reducing the risk of dielectric breakdown in various configurations of the circuit breaker. This risk can be reduced by increasing the distance between elements that are on different potentials within the circuit breaker. Such an increased distance, however, has a number of disadvantages such as more need for space and for insulation gas (e.g. SF6), higher manufacturing cost, longer switching times and/or need for a stronger drive.